From f5c5b73895b68d8c6fd032a4fd5f98a9e5fb8a4a Mon Sep 17 00:00:00 2001
From: Nir Soffer <nsoffer@redhat.com>
Date: Jun 17 2019 14:05:45 +0000
Subject: python: Streamline initexception


When we create the sanlock exception we create a function, create a
method from the function, create a dict from the method, and finally
create an exception from the dict. This simple flow does not require
goto for cleanup.

Creating a dict is simpler and less error prone using Py_BuildValue().

When we finish with unused pointers, it is safer to set them to NULL
using Py_CLEAR(), ensuring that we don't access freed memory.

Signed-off-by: Nir Soffer <nsoffer@redhat.com>

---

diff --git a/python/sanlock.c b/python/sanlock.c
index 21a7a76..5c2fd1a 100644
--- a/python/sanlock.c
+++ b/python/sanlock.c
@@ -1743,29 +1743,22 @@ sanlock_exception = {
 static PyObject *
 initexception(void)
 {
-    int rv;
-    PyObject *dict, *func, *meth, *excp = NULL;
-
-    if ((dict = PyDict_New()) == NULL)
-        goto exit_fail;
-
-    if ((func = PyCFunction_New(&sanlock_exception, NULL)) == NULL)
-        goto exit_fail;
+    PyObject *func = PyCFunction_New(&sanlock_exception, NULL);
+    if (func == NULL)
+        return NULL;
 
-    meth = PyObject_CallFunction((PyObject *) &PyProperty_Type, "O", func);
-    Py_DECREF(func);
+    PyObject *meth = PyObject_CallFunction((PyObject *) &PyProperty_Type, "O", func);
+    Py_CLEAR(func);
     if (meth == NULL)
-        goto exit_fail;
-
-    rv = PyDict_SetItemString(dict, sanlock_exception.ml_name, meth);
-    Py_DECREF(meth);
-    if (rv < 0)
-        goto exit_fail;
+        return NULL;
 
-    excp = PyErr_NewException("sanlock.SanlockException", NULL, dict);
+    PyObject *dict = Py_BuildValue("{s:O}", sanlock_exception.ml_name, meth);
+    Py_CLEAR(meth);
+    if (dict == NULL)
+        return NULL;
 
-exit_fail:
-    Py_XDECREF(dict);
+    PyObject *excp = PyErr_NewException("sanlock.SanlockException", NULL, dict);
+    Py_CLEAR(dict);
 
     return excp;
 }